The principal proposes in this R15 competing renewal to evaluate mechanisms of brain zinc Zn) homeostasis maintenance. Zinc transport will be assessed in an in vitro model of the blood brain barrier (BBB) under different conditions of Zn status. Both brain uptake and brain to blood transport will be determined. The proposal also seeks to evaluate Zn transporter expression through Northern, Western and 2-D PAGE analysis from the in vitro BBB model and by isolating brain capillaries from the brains of minipigs subjected to varying Zn conditions.